Improve Base collection, model and repository

- Add collection pipeline methods
- Add save collection method

src/BaseCollection.php

@@ -28,6 +28,30 @@ abstract class BaseCollection extends \ArrayIterator
 		$this->totalCount = $totalCount ?? count($models);
 	}
 
+	/**
+	 * @inheritDoc
+	 */
+	public function offsetSet($offset, $value)
+	{
+		if (is_null($offset)) {
+			$this->totalCount++;
+		}
+
+		parent::offsetSet($offset, $value);
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function offsetUnset($offset)
+	{
+		if ($this->offsetExists($offset)) {
+			$this->totalCount--;
+		}
+
+		parent::offsetUnset($offset);
+	}
+
 	/**
 	 * @return int
 	 */
@@ -35,4 +59,42 @@ abstract class BaseCollection extends \ArrayIterator
 	{
 		return $this->totalCount;
 	}
+
+	/**
+	 * Return the values from a single field in the collection
+	 *
+	 * @param string   $column
+	 * @param int|null $index_key
+	 * @return array
+	 * @see array_column()
+	 */
+	public function column($column, $index_key = null)
+	{
+		return array_column($this->getArrayCopy(), $column, $index_key);
+	}
+
+	/**
+	 * Apply a callback function on all elements in the collection and returns a new collection with the updated elements
+	 *
+	 * @param callable $callback
+	 * @return BaseCollection
+	 * @see array_map()
+	 */
+	public function map(callable $callback)
+	{
+		return new static(array_map($callback, $this->getArrayCopy()), $this->getTotalCount());
+	}
+
+	/**
+	 * Filters the collection based on a callback that returns a boolean whether the current item should be kept.
+	 *
+	 * @param callable|null $callback
+	 * @param int           $flag
+	 * @return BaseCollection
+	 * @see array_filter()
+	 */
+	public function filter(callable $callback = null, int $flag = 0)
+	{
+		return new static(array_filter($this->getArrayCopy(), $callback, $flag));
+	}
 }